H.A.C. - Hot Air Cooling
In the float glass process, the glass ribbon is cooled down from 1100°C to 600°C during the forming on the tin bath. A part of the heat is evacuated by water coolers, inserted through the side walls. Simultaneously, electrical heaters in the crown allow for the fine adjustment of the ribbon temperature profile and for bath heating during ribbon stops.
The water coolers have to be inserted or removed for every adjustment of the ribbon temperature exceeding the resistance heater capacity. In the case of a ribbon stop, all coolers have to be removed quickly.
Fives developed new, proprietary heat exchangers that operate with air instead of water.
This new technology has a series of advantages:
- The hot air extracted from the coolers can be used for energy recovery.
- The pressure in the coolers is reduced compared to the water coolers eliminating leakage risk.
- The cooling rate can be adjusted by the air flow thus allowing a fine adjustment of the ribbon temperature - with all coolers in place.
- The coolers can even stay in place in case of a ribbon stop.
- The higher surface temperature of the coolers reduces tin condensation and the risk of ribbon defects.
The new hot air coolers can be integrated in a new tin bath or replace in an existing tin bath the water coolers or boost the cooling capacity.
Last but not least, the coolers can be converted to heaters ! This allows reducing or suppressing the costly resistance heating in the bath roof. Moreover, the costly and maintenance intensive water cooling circuit for the tin bath can be downsized.